JP2005118727A - Oil polluted soil treatment method and treatment system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an oil polluted soil treatment system which removes efficiently oil content from oil polluted soil, and can carry out the accompanying aftertreatment such as neutralization treatment of a cleaning liquid safely and simply. <P>SOLUTION: The oil polluted soil treatment system is provided with a first treatment machine 1 where unslaked lime or additives containing mainly unslaked lime are added to the oil polluted soil and mixed, a second treatment machine 2 which receives the oil polluted soil mixed in the first treatment machine 1, and removes, by volatilizing and transpiring, a volatile component from the oil content contained in the soil by means of a hydration reaction heat generated between the moisture in the soil and the unslaked lime or additives containing mainly unslaked lime, and a third treatment machine 5 which receives the oil polluted soil treated in the second treatment machine 2, washes the treated polluted soil, and peels off and separation-removes the remained nonvolatile oil content from the soil. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a method and a processing system for treating soil contaminated with oil.

  In recent years, with the redevelopment of factory sites, problems of soil contamination due to heavy metals, volatile organic compounds, and specific hazardous substances such as oils have become apparent, and measures to prevent soil contamination are concerned due to concerns about health effects. In February 2003, the Soil Contamination Countermeasures Law was enforced. This soil pollution control law obligates land surveys when abolishing facilities that use hazardous substances, and orders surveys even for facilities that are in use that may cause health damage due to soil contamination. be able to. As a result of the survey, the land where contamination is found is listed as a contaminated area in the designated area register, and the landowner must take necessary countermeasures.

  On the other hand, soil contamination due to oils is not included in the above countermeasures, but the oil film and oil odor affect the living environment and are often recognized as soil contamination. It is highly likely that some kind of standard will be designated as a substance. Therefore, as a measure for treating soil contaminated with oil, there is a method of mixing contaminated soil and an additive to volatilize and remove harmful volatile oil (for example, see Patent Document 1).

JP 2003-71426 A

  However, there is a grudge that the oil contained in the fine soil block cannot be sufficiently volatilized only by the mixing treatment of the soil and the additive as in Patent Document 1 described above. That is, in the course of the mixing treatment, the oil that has not come into contact with the additive remains in the soil. In addition, volatile light oil may be contained in the contaminated soil. If even a small amount of volatile light oil remains in this contaminated soil, an oil film and an oily odor will be generated. To do. In the method according to the prior art described above, it is difficult to remove this light oil to such an extent that it does not generate an oil film and an oily odor, and therefore, a proposal for a measure for quickly removing a sufficient oil content is desired.

  The present invention has been made in view of the above-described matters, and the object thereof is to enable efficient purification treatment regardless of the type of oil, and to safely and easily perform post-treatment such as neutralization of a cleaning liquid. It is an object of the present invention to provide a method and a system for treating oil-contaminated soil that can be used in the present invention.

  In order to achieve the above object, the first invention heats soil contaminated with oil, volatilizes and removes volatile components from the oil contained in the soil, and then treats the contaminated soil. Is a method for treating oil-contaminated soil, characterized in that the remaining non-volatile oil is separated and removed from the soil.

  In addition, the second invention is the addition of quicklime or quicklime as a main component to the soil contaminated with oil, and the addition of the quicklime or quicklime as a main component to the soil. Heat using heat generated by the hydration reaction that occurs between the water and the volatile components of the oil contained in the soil is removed by volatilization and transpiration, and then the treated contaminated soil is washed, It exists in the processing method of oil-contaminated soil characterized by peeling and isolate | separating and removing the remaining non-volatile oil component from soil.

  Further, according to the third aspect of the present invention, a hydration reaction that takes place between moisture in the oil-contaminated soil and the additive material is performed by adding and mixing quick lime or an additive material composed mainly of quick lime into the soil contaminated with oil. The heat generated by the oil is used to heat and volatilize and evaporate volatile components of the oil contained in the soil, and then the treated contaminated soil is washed to remove and separate the remaining non-volatile oil from the soil. It exists in the processing method of the oil-contaminated soil characterized by removing.

  In addition, the fourth invention is the addition of an additive mainly composed of quick lime or quick lime to the soil contaminated with oil, and an additive mainly composed of moisture in the oil-contaminated soil and quick lime or quick lime. The heat generated by the hydration reaction that takes place between the oil is removed by volatilizing and removing the volatile components from the oil contained in the soil, and reacting with the additive and the moisture in the soil. After transferring the non-volatile oil remaining in the soil to the slaked lime with increased surface area, the treated contaminated soil is washed and the remaining non-volatile oil is peeled off and separated from the soil. The feature is a method for treating oil-contaminated soil.

  Furthermore, the fifth invention is the addition of an additive mainly composed of quick lime or quick lime to the soil contaminated with oil, and an additive mainly composed of moisture and quick lime or quick lime in the oil-contaminated soil. The heat generated by the hydration reaction that takes place between the oil is removed by volatilizing and evaporating volatile components from the oil contained in the soil, and reacting with the additive and moisture in the soil. After transferring the non-volatile oil remaining in the soil to the slaked lime with increased surface area, the treated contaminated soil is washed and the slaked lime adsorbing the non-volatile oil in the soil is dissolved in the cleaning solution In addition, the present invention provides a method for treating oil-contaminated soil, characterized by separating and separating and removing residual non-volatile oil from the soil.

  Further, the sixth invention is that in any one of the first to fifth inventions, the temperature of the cleaning liquid is increased by receiving heated soil, and the cleaning treatment efficiency of the contaminated soil is improved. The feature is a method for treating oil-contaminated soil.

  Furthermore, a seventh aspect of the present invention is the method according to any one of the first to fifth aspects, wherein the slaked lime generated by the reaction with the moisture in the soil is put into the cleaning treatment step so that the slaked lime is contained in the cleaning liquid. The oil-contaminated soil treatment method is characterized by increasing the pH of the washing solution and improving the washing treatment efficiency of the contaminated soil.

  In addition, the eighth aspect of the present invention is to add and mix quick lime or an additive mainly composed of quick lime to the soil contaminated with oil, and by this mixing, A first processor that uses heat generated by a hydration reaction that occurs with moisture to heat and removes volatile components from the oil contained in the soil by volatilization and transpiration, and the first treatment. Oil that has been treated with a machine, has a second treatment machine that receives the oil-contaminated soil, cleans the treated-contaminated soil, and separates and separates the remaining non-volatile oil from the soil. In the contaminated soil treatment system.

  Furthermore, 9th invention adds the oil lime or the additive which has quick lime as a main component to the soil contaminated with oil, and the oil pollution mixed with this 1st processing machine which adds and mixes. Accepts the soil and heats it using the heat generated by the hydration reaction between the quicklime or the additive containing quicklime as the main component and the moisture in the soil, and removes the volatile components from the oil contained in the soil. The second treatment machine that is removed by volatilization and transpiration and the oil-contaminated soil treated by the second treatment machine are received, the treated contaminated soil is washed, and the remaining non-volatile oil is separated from the soil. -It exists in the processing system of the oil-contaminated soil characterized by including the 3rd processing machine to separate and remove.

  According to the treatment method of the present invention, it is possible to efficiently remove oil from the soil contaminated with oil, and post-treatment of the cleaning liquid can be performed safely and easily.

  According to the treatment system of the present invention, oil can be efficiently removed from soil contaminated with oil, and the treatment efficiency can be improved.

  Hereinafter, embodiments of a treatment system and a treatment method for oil-contaminated soil according to the present invention will be described with reference to the drawings.

  FIG. 1 is a front view showing an embodiment of a treatment system for oil-contaminated soil according to the present invention. In FIG. 1, reference numeral 1 denotes a first processing unit that processes contaminated soil. The first processing unit 1 receives soil and sand to be purified by a work tool such as a bucket of a hydraulic excavator S, for example. Then, a predetermined additive (one that reacts with moisture to generate heat, typically, for example, quick lime) is added to and mixed with the introduced earth and sand. Reference numeral 2 denotes a second processing machine that volatilizes volatile oil in the mixed sediment transported from the mixing processing machine 1, and this second processing machine 2 has a tent-like shape forming a substantially sealed space inside. It is comprised by the surrounding means 3 and the conveyor 4 provided in this surrounding means 3. FIG. Reference numeral 5 denotes a third processing machine, and this third processing machine 5 is a contaminated soil cleaning processing machine that receives primary-treated earth and sand conveyed by the conveyor 4 and performs a cleaning process. 6 is a catalytic cracking device connected to the surrounding means 3, and this catalytic cracking device 6 processes the volatilized oil. Reference numeral 7 denotes clean soil processed by the third processing machine 5.

  The configuration of the first processor 1 will be described with reference to FIGS. 2 and 3. FIG. 2 is a front view of the first processing machine 1, and FIG. 3 is a diagram in which a traveling body (described later), a main body frame (described later), an earth and sand hopper (described later), a power unit (described later), etc. are omitted in the first processing machine 1. FIG.

  In FIG. 2, 10 is a sieving device that sorts the introduced earth and sand according to the particle size, 11 is an earth and sand hopper that receives the earth and sand selected by the sieving device 10, and 12 is a predetermined additive for the earth and sand introduced from the earth and sand hopper 11 A mixing device that mixes and discharges to the rear side (right side in FIG. 2; hereinafter, simply referred to as “rear side” as appropriate), 13 is a carry-in conveyor that conveys and introduces the earth and sand received in the earth and sand hopper 11 to the mixing device 12; 14 is an additive supply device for supplying an additive, 15 is a traveling body in the first processor 1, and 16 is a first that receives mixed processing soil mixed by the processing mixing device 12 and discharged to the rear side. It is a carry-out conveyor which conveys to the back side of the processing machine 1, and discharges.

  The traveling body 15 includes an endless track crawler belt 18 provided on both sides of the main body frame 17. The endless track crawler belt 18 is stretched between a driving wheel 19 and a driven wheel 20. A traveling hydraulic motor 21 is connected to the drive wheel 19 side.

  In the present embodiment, it is assumed that the contaminated soil is intermittently charged by a hydraulic excavator etc. Although the so-called crawler type traveling means provided with 18 has been taken as an example, for example, when earth and sand are continuously charged using a conveyor or the like, it may be used instead of the so-called wheel type traveling means. Is possible.

  Next, the details of each component described above will be described. The sieve device 10 is a so-called vibrating sieve that can vibrate in the vertical direction, and together with the earth and sand hopper 11, above the front side (left side in FIG. 2, hereinafter, simply referred to as the front side as appropriate) of the main body frame 17. It is installed. Specifically, the sieving device 10 includes a support frame 22 elastically supported via a spring 23 on a support member 22 provided on the main body frame 17, and a lattice member 25 attached to the support frame 24. And a rotating drum 26 having a vibrating shaft (not shown) of the lattice member 25 inserted therein, and a vibration hydraulic motor 27 for generating a driving force for rotating the rotating drum 26. Yes.

  Then, the driving force of the vibration hydraulic motor 27 is transmitted to the rotating drum 26 via the belt 28 and rotated, so that the vibration shaft of the lattice member 25 inserted into the rotating drum 26 vibrates. Thereby, the earth and sand thrown into the sieving apparatus 10 by, for example, a hydraulic excavator is also subjected to an action by vibration, and the earth and sand components smaller than the eyes of the lattice member 25 are guided downward, for example, a lattice such as concrete, rock, or metal. Solid foreign matters larger than the eyes of the member 25 are removed. The solid foreign matter remaining on the lattice member 25 by this sorting moves forward along the inclination of the lattice member 25 and falls.

  Depending on the environment at the work site and the nature of the earth and sand, there may be no large solid foreign matter. In that case, the sieve device 10 does not need to be provided, and only the earth and sand hopper 11 may be used.

  Next, the configuration of the carry-in conveyor 13 will be described. The carry-in conveyor 13 is mounted on the front side end of the main body frame 17 and is located almost directly below the earth and sand hopper 11 and the sieve device 10. The carry-in conveyor 13 is low on the upstream side (left side in FIG. 2) and high on the downstream side (right side in FIG. 2), and includes a conveyor frame 29 and a carry-in conveyor hydraulic motor (supported by the conveyor frame 29). A conveyance belt 32 wound around a drive wheel 30 and a driven wheel 31 driven by a not-shown) and a guide roller 33 for supporting a conveyance surface of the conveyance belt 32 are provided. . The guide roller 33 is a fixed roller that is supported by the conveyor frame 29 and abuts on the back surface of the transport surface of the transport belt 32 and rolls by the feed, and a plurality of guide rollers 33 are arranged with a predetermined pitch interval. The carry-in conveyor 13 includes a known adjustment mechanism on the driven wheel 31 side so that the tension of the conveyance belt 32 can be adjusted as appropriate.

  Next, the configuration of the additive supply device 14 will be described. The additive supply device 14 is located on the rear side of the sieving device 10 and is mounted on a substantially middle portion in the longitudinal direction of the main body frame 17. More specifically, the additive supply device 14 is supported by a substantially rectangular base plate 35 provided on a plurality of (for example, four) columns 34 erected on the main body frame 17. The additive supply device 14 includes a storage tank 36 that stores a predetermined amount of additive, and a feeder 37 that is connected to the lower portion of the storage tank 36 and supplies the additive by a predetermined amount.

  The storage tank 36 is generally cylindrical in shape and has a space for storing the additive therein, and has a bottomed cylindrical lower tank portion 38 installed on the base plate 35 on the lower side, and a substantially circular shape. The top plate portion 39, and the bellows portion 40 as an upper tank portion having a variable upper volume provided between the lower tank portion 38 and the top plate portion 39. A substantially circular opening (not shown) is formed in the central portion of the top plate portion 39, and an open / close lid 41 that can be opened in both directions is provided above the opening. When filling the storage tank 36 with the additive, the open / close lid 41 is opened, the flexible container is lifted by a crane or the like separately prepared, and inserted into the storage tank 36 through the opening, and the internal additive is introduced into the storage tank 36. Supply.

  The tank section 38 is provided with a bottom plate 43 having an additive supply opening 42 having a predetermined opening diameter, and the additive is introduced into the feeder 37 through the additive supply opening 42 in the previous period.

  The feeder 37 has a casing 44 fixed to the lower surface portion of the additive supply opening 42 in the bottom plate 43 of the storage tank 36. The casing 44 has an inflow port 45a that communicates with the additive material supply opening 42 and a supply port 45b that opens downward, and an intermediate wall surface is an arc-shaped constant supply unit 45c. A rotor (not shown) is provided inside the quantitative supply unit 45c, and the rotor is rotated by a feeder motor (not shown) made of a variable speed electric motor, for example. The amount of additive material corresponding to the amount is added on the carry-in conveyor 13 to the earth and sand supplied from the earth and sand hopper 11 through the supply port 45b.

  Next, the configuration of the mixing device 12 will be described with reference to FIG. The mixing device 12 is provided in the middle in the longitudinal direction of the main body frame 17 in FIG. 2, and includes a mixing device main body 46 composed of a rectangular container arranged in a substantially horizontal direction, and a front side of the mixing device main body 46 ( (Middle left side) An upper portion, an introduction portion 47 for introducing earth and sand and additive material conveyed by the conveyance belt 32 of the carry-in conveyor 13, and a discharge portion 48 provided at the lower rear side of the mixing device main body 46. And an even number (for example, two) of paddle mixers 49 provided in parallel in the mixing device main body 46.

  The paddle mixer 49 has a rotating shaft 50, a plurality of blades (stirring blades, paddles) 51 provided intermittently as stirring / mixing / transfer members on the rotating shaft 50, and both ends of the rotating shaft 50 are rotatable. Supporting bearings 52 and 52 are provided.

  At this time, the rear end portion of the rotary shaft 50 extends into a drive unit 53 provided at the rear end portion of the mixing apparatus main body 46. A transmission gear 54 is connected to the rear end of each rotary shaft 50, and the transmission gears 54 of the paddle mixers 49 mesh with each other. One transmission gear 54 is connected to the output shaft of the mixing device hydraulic motor 55. By rotating the mixing device hydraulic motor 55, the rotation shafts 50 of the paddle mixers 49 are simultaneously and mutually connected. It is designed to rotate in the opposite direction.

  At this time, a large number of the paddles 51 are installed on the outer peripheral surface of each rotating shaft 50 at a predetermined angle in the circumferential direction, and the paddle 51 is rotated by rotating the rotating shaft 50 as described above. The earth and sand introduced into the mixing device main body 46 and the additive are agitated and uniformly mixed and transferred toward the discharge portion 48 side.

  As described above, the earth and sand introduced from the introduction portion 47 of the mixing device body 46 and the additive are uniformly stirred and mixed by the action of the paddle mixer 49, and are transferred toward the discharge portion 48. In the meantime, the primary treated soil is discharged from the discharge unit 48 onto the carry-out conveyor 16 by its own weight.

  Next, the structure of the carry-out conveyor 16 mentioned above is demonstrated using FIG. 2 and FIG. The carry-out conveyor 16 has a portion near the end on the discharge side (right side in FIG. 2) located on the rear side (right side in FIG. 2) from the mixing device 12 and on the main body frame 17 via the power unit stacking member 56. The power unit 57 is suspended and supported via a support member (not shown). Further, the portion in the vicinity of the end opposite to the discharge side and the intermediate portion in the transport direction are located below the main body frame 17 and extend horizontally by a short distance in the discharge direction, and then the outer edge of the power unit 57. In the lower space of the (rear end portion), it is arranged so as to rise obliquely upward in the discharge direction (right side in FIG. 2). Similarly to the carry-in conveyor 13, the carry-out conveyor 16 is wound between a conveyer frame 58, a drive wheel 60 supported by the conveyer frame 58 and driven by a carry-out conveyer hydraulic motor 59 and a driven wheel (not shown). A conveyor belt 61 that is rotated and a guide roller (not shown) for supporting the conveyor surface of the conveyor belt 61 are provided. The guide rollers are fixed rollers that are supported by the conveyor frame 58, abut on the back side of the transport surface of the transport belt 61, and roll by the feed, and a plurality of guide rollers are arranged with a predetermined pitch interval. Similarly to the carry-in conveyor 13, the carry-out conveyor 16 also includes a known adjustment mechanism on the driven wheel side so that the tension of the conveyance belt 61 can be adjusted as appropriate.

  With the structure as described above, the carry-out conveyor 16 drives the conveyor belt 61 by the hydraulic motor 59 for the carry-out conveyor, thereby conveying the primary treated soil that has fallen onto the conveyor belt 61 from the mixing device 12. It is like that.

  Here, the sieve device 10, the mixing device 12, the carry-in conveyor 13, the carry-out conveyor 16, and the left / right endless track crawler belt 18 are a power source provided in the self-propelled contaminated soil mixing treatment machine, that is, an engine as a prime mover. (Not shown) and driven by power from at least one hydraulic pump (not shown) driven by the engine. Pressure oil from the hydraulic pump is supplied to the sieve device 10, the mixing device 12, the carry-in conveyor 13, and the carry-out conveyor via a control valve device (not shown) having a control valve for controlling the direction and flow rate of the pressure oil. 16 and the crawler crawler belt 18 respectively corresponding to the excitation hydraulic motor 27, the mixing device hydraulic motor 55, the carry-in conveyor hydraulic motor (not shown), the carry-out conveyor hydraulic motor 59, and the left / right traveling This is supplied to the hydraulic motor 21, whereby the corresponding hydraulic motor is driven to rotate. The engine, the hydraulic pump, and the control valve device are all provided in the power unit 57.

  A driver's seat (not shown), which is a section on which an operator is boarded, is provided in a region on the front side (left side in FIG. 2) of the power unit 57. In the driver's seat, operating means for controlling the driving speed of the left / right traveling hydraulic motor 21 by switching a left / right traveling control valve (not shown) provided in the control valve device. Left and right operation levers (not shown) are provided.

  The 1st processing machine 1 mentioned above is the primary state in which the earth and sand contaminated with oil are mixed with quick lime, the volatile component of the oil is removed by volatilization, and the non-volatile oil is transferred to slaked lime. It is carried out to the 2nd processing machine 2 as processing soil. The primary treated soil transported into the second processing machine 2 is put into the belt conveyor 4 in the surrounding means 3. The belt conveyor 4 has a function of curing the primary treated soil and promoting volatilization, and a function of carrying the primary treated soil into the second processing machine 5.

  The enclosing means 3 constituting the second processor 2 is provided with a catalyst decomposing apparatus 6 for treating the oil component volatilized in the enclosing means 3, and the adsorption process of the gas volatilized by the catalytic decomposing apparatus 6. Is done.

  Next, the configuration of the third processor 5 will be described with reference to FIGS. 4 and 5. 4 is a front view of the third processing machine 5, and FIG. 5 is a front view of the third processing machine 5 in which a traveling body (described later), a main body frame (described later), an earth and sand hopper (described later), a power unit (described later), and the like are omitted. In FIG. 4, reference numeral 62 denotes traveling means that enables self-running, and has the same configuration as the traveling body 15 in the first processing machine 1. In the present embodiment, a so-called crawler type traveling means is illustrated. However, in the case where earth and sand are carried from the belt conveyor 4 as in the present embodiment, the soil is contaminated by a hydraulic excavator or the like. Unlike the case where the vehicle is intermittently charged, the vehicle body does not become unstable due to the impact load or the like when the earth and sand is charged. Therefore, it may be replaced with a so-called wheel-type traveling means.

  Reference numeral 63 denotes a main body frame for supporting various mechanisms and devices. A primary processing soil and cleaning liquid supply unit 64 is provided on one side of the main body frame 63 in the longitudinal direction, a processing mechanism unit 65 is provided at a substantially central portion thereof, and a rear side of the processing mechanism unit 65 is directed rearward. A discharge part 66 is provided.

  The supply unit 64 includes a soil / sand supply unit 67 that supplies the supplied primary processing soil to the processing mechanism unit 65, and a cleaning liquid supply unit 68 that serves as a cleaning liquid supply unit that supplies a cleaning liquid to the processing mechanism unit 65. Yes. The earth and sand supply unit 67 is equipped with the sieve device 69, the earth and sand hopper 70, and the carry-in conveyor 71 having the same configuration as the sieve device 10, the earth and sand hopper 11, and the carry-in conveyor 13 that are mounted on the first processing machine 1. Thus, the charged primary processing soil is conveyed to the processing mechanism unit 65. However, since the primary treatment soil subjected to the cleaning treatment by the third treatment machine 5 has already been subjected to the primary treatment by the first treatment machine 1, solid foreign matters such as concrete, rock, metal, etc. Does not exist. Therefore, the sieving device 69 may not be mounted, and may be configured such that the primary treated soil is poured directly into the earth and sand hopper 70.

  As shown in FIG. 5, the cleaning liquid supply unit 68 includes a cleaning liquid tank 95 and a liquid supply unit 72 that supplies the cleaning liquid in the liquid tank 95 to the processing mechanism unit 65.

  The liquid tank 95 is provided below the earth and sand supply unit 67 and is directly supported on one side in the longitudinal direction of the main body frame 63.

  An inflow conduit 73 through which the cleaning liquid in the processing mechanism section 65 flows is provided at the upper part of the liquid tank 68, and a plurality of strainers 75 located slightly below the cleaning liquid level provided in a processing tank 74 described later. Then, the cleaning liquid is sucked into the liquid tank 68 by the liquid suction part 76. In addition, the liquid suction part 76 is comprised by the spiral pump, for example.

  In the present embodiment, the cleaning liquid inflow method in the processing tank 74 uses suction by a centrifugal pump. However, the cleaning liquid inflow method may be performed by using the water level difference between the cleaning liquid level in the processing tank 74 and the liquid tank 68. .

  The bottom plate 77 of the liquid tank 68 has a substantially quadrangular pyramid shape, and solids in the liquid tank 68 are collected in a collection case 79 via a cylindrical body 78 attached to the bottom plate 77.

  A stirring device 80 is provided in the liquid tank 68. The stirring device 80 functions to stir the aggregating agent and the cleaning liquid described later. Further, an oil recovery device 81 is provided in the liquid tank 68 for recovering the oil floating on the liquid level in the liquid tank. The oil recovery device 81 is equipped with a float, and is configured to follow the fluctuation of the liquid level in the liquid tank by the buoyancy of the float.

  Further, a partition wall 82 that is slightly lower than the liquid level in the tank is provided in the liquid tank 68, and the supernatant liquid that has passed over the partition wall 82 of the liquid tank section is sent to the liquid supply section 72 described later.

  The liquid supply part 72 is constituted by a centrifugal pump and may be the same as the liquid suction part 76. The cleaning liquid in the liquid tank 68 is supplied to the treatment tank 74 through the water supply pipe 83 by the liquid supply unit 72.

  Reference numeral 84 denotes a coagulant supply unit. The coagulant supply unit 84 is equipped with an impeller-type flow meter (not shown). The flow meter detects the flow rate based on the number of rotations and controls the dripping amount of the flocculant. As a result, fine particles of earth and sand contained in the cleaning liquid sucked by the liquid sucking unit 76 are agglomerated and precipitated.

  85 is provided at the upper part on the front side of the processing tank 74, and is an inlet for introducing the primary processing soil sent from the carry-in conveyor 71, and 86 is an outlet provided at the lower part on the rear side of the processing tank 74. The treatment tank 74 has a watertight structure except for the introduction port 85 and the discharge port 86, and the lower side thereof is formed in a substantially arc-shaped cross section along the rotation locus of a paddle mixer 87 (described later). Yes. A water level sensor 88 is provided on the inner wall of the processing tank 74 and serves as a water level detecting means for detecting the water level of the cleaning liquid stored in the processing tank 74.

  Reference numeral 87 denotes a paddle mixer provided in the treatment tank 74. The paddle mixer 87 has a structure similar to that of the paddle mixer 49 mounted on the contaminated soil mixing processing machine 1, and the paddle mixer 49 allows the inside of the washing tank 74 to be installed. Then, by stirring and washing the primary treated soil, the oil remaining in the primary treated soil is further separated and removed.

  The discharge section 66 is a discharge means for discharging the earth and sand discharged from the processing mechanism section 65 to the outside of the machine, and a screw conveyor 89 is used in the present embodiment. 90 is a substantially cylindrical casing constituting the main body of the screw conveyor 89, and on the upstream side in the transfer direction of the casing 90, there is an upward inlet 91 that is water-tightly connected to the discharge port 86 of the treatment tank 74 via a discharge valve (not shown). A downward outlet 92 is provided on the downstream side. At this time, the casing 90 is moved from the lower position of the processing mechanism unit 65 to the sediment transfer direction (see FIG. 5) so that the height of the outlet 92 is higher than the cleaning liquid level (symbol ▽ in the drawing) in the processing tank 74. 5 in the right direction).

  With the above configuration, the screw conveyor 89 conveys only the washed sand and sand from the processing mechanism unit 65 while dehydrating it without leaking the cleaning liquid in the processing tank 74, and discharges it to the outside through the outlet 92. It has become.

  Next, the processing method by one Embodiment of the processing system of the oil-contaminated soil of this invention mentioned above is demonstrated. First, when excavating soil contaminated with oil by, for example, a hydraulic excavator S and putting it into the sieving apparatus 10 in the first processing machine 1, large rubble or the like is removed by the lattice member 25 and passed through the lattice member 25. The earth and sand are introduced into the earth and sand hopper 11 below.

  The soil received by the earth and sand hopper 11 is placed on the conveyor belt 32 of the carry-in conveyor 13 below and conveyed toward the rear side. Then, in the vicinity of the downstream end of the carry-in conveyor 13 in the carrying direction, a predetermined amount of additive (quick lime or an additive containing quick lime as a main component) is added from the storage tank 36 through the feeder 37 to the surface of the carrying soil. These mixed earth and sand are introduced into the mixing device 12.

Contaminated earth and sand introduced into the mixing device 12 and the additive (quick lime or additive mainly composed of quick lime) are uniformly stirred and mixed by the paddle mixer 49 in the mixing device main body 46, and the additive represented by the following formula: The reaction between quick lime, which is the main component of lime, and moisture contained in the earth and sand is started, and heat of reaction is generated.
CaO + H ₂ O → Ca (OH) ₂ + reaction heat The entire soil is heated by this reaction heat, so that volatile and transpiration are separated for highly volatile components in the oil contained in the contaminated sediment. Is removed from the soil. Quick lime is converted to slaked lime by reacting with moisture contained in the earth and sand, but since slaked lime is very fine particles, its specific surface area is very large. Therefore, the non-volatile components remaining in the earth and sand are attached to and transferred to slaked lime using the mechanical action during the stirring and mixing by the paddle mixer 49.

  The earth and sand treated as described above is discharged from the discharge conveyor 16 as the primary treated soil, and is carried into the belt conveyor 4 in the surrounding means 3 constituting the second processor 2.

  While the primary treated soil put into the belt conveyor 4 is transported to the third processing machine 5 by the belt conveyor 4, the volatile component of oil is volatilized and removed by the reaction heat. The volatilized oil is decomposed in the catalyst decomposition device 6.

  Next, the firstly processed earth and sand put into the third processing machine 5 by the belt conveyor 4 is washed in the third processing machine 5. The cleaning processing operation will be described next. The primary processing soil carried into the earth and sand hopper 70 of the third processing machine 5 is filled with a necessary amount of water as a cleaning liquid in advance by the carry-in conveyor 71. And a stirring cleaning process by the paddle mixer 87 is performed. Here, by utilizing the fact that slaked lime is dissolved in water, the non-volatile component of the oil that has been transferred to the slaked lime is floated on the liquid surface of the cleaning liquid and collected.

  In addition, slaked lime dissolves in water, which is a cleaning solution, and the cleaning solution becomes a strong alkali. By the effect of alkali (reduction in surface tension, saponification, etc.), oil remaining in the earth and sand is separated and removed, and only water is used as the cleaning solution Compared with the case of using, a more effective cleaning process is possible.

  Furthermore, the temperature of the earth and sand of the primary treated soil is increased by the reaction heat. Accordingly, since the viscosity of the remaining oil is reduced, the oil is easily peeled off from the soil particles, and further, the primary treated soil holding this heat is put into the third processing machine 5. Then, the temperature of the cleaning liquid in the treatment tank 74 can be increased by the residual heat of the earth and sand by being conveyed to the treatment tank 74. As a result, the agitation cleaning process by the paddle mixer 87 facilitates oil separation / separation and removal, and a highly effective cleaning process is possible, so that a cleaner soil can be obtained.

  Thus, the earth and sand subjected to the stirring and washing process in the treatment tank 74 is discharged from the discharge unit 66 as the clean soil 7. As a result, according to the treatment method of the present invention, it is possible to efficiently remove oil from the soil contaminated with oil, and it becomes possible to safely and easily perform post-treatment of the cleaning liquid. Further, according to the treatment system of the present invention, it is possible to efficiently remove oil from the soil contaminated with oil, and the treatment efficiency can be improved.

In addition, the cleaning liquid after performing the cleaning process by the third processing machine 5 is strong alkali because slaked lime is dissolved, but this water-soluble slaked lime, that is, calcium hydroxide is carbon dioxide. The following reaction is carried out by performing the aeration process according to, and it can be taken out as calcium carbonate, so that it can be easily neutralized.
Ca (OH) ₂ + CO ₂ → CaCO ₃ + H ₂ O
Since calcium carbonate (CaCO ₃ ) produced by this reaction is a harmless substance, it can be recovered in the same manner as the fine particles that are aggregated by the flocculant during the cleaning process. In addition, although carbon dioxide in the air may be used as the carbon dioxide, in order to promote the above reaction between slaked lime and carbon dioxide, the power units of the first processor 1 and the third processor 5 are provided. Exhaust gas from the engine can also be used.

  In addition, it is preferable to reuse the cleaning liquid after use, but the third processor 5 in the present embodiment is configured to be able to purify and reuse the cleaning liquid. By purifying and reusing the cleaning liquid while performing the aeration process, it can be applied in the field where it is difficult to secure an external water source.

  In the above-described embodiment, the second processor 2 is provided between the first processor 1 and the third processor 5 to promote and recover the oil volatilization. It is also possible to mount the processor 2 in the first processor 1. According to this embodiment, since the installation space of each processing machine becomes small, processing in a narrow space is also possible.

It is a front view showing one embodiment of a processing system of oil pollution soil of the present invention. It is a front view which expands and shows the 1st processing machine which comprises the processing system of the oil-contaminated soil of this invention shown in FIG. It is a front view which shows the main process mechanism part of the 1st processing machine which comprises the processing system of the oil-contaminated soil of this invention shown in FIG. It is a front view which expands and shows the 3rd processing machine which comprises the processing system of the oil-contaminated soil of this invention shown in FIG. It is a front view which shows the main process mechanism part of the 3rd processing machine which comprises the processing system of the oil-contaminated soil of this invention shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 1st processing machine 2 2nd processing machine 3 Surrounding means 4 Belt conveyor 5 3rd processing machine 6 Catalyst decomposition apparatus 7 Clean soil

Claims (9)

  The soil contaminated with oil is heated to remove volatile components by volatilization and transpiration from the oil contained in the soil, and then the treated contaminated soil is washed to remove the remaining non-volatile oil from the soil. A method for treating oil-contaminated soil, characterized by peeling and separating.   Water that occurs between quick lime or quick lime-based additives and water in the soil by adding and mixing quick lime or quick lime-based additives to the soil contaminated with oil Heat generated by the sum reaction is heated to remove volatile components by volatilizing and evaporating from the oil contained in the soil, then washing the treated contaminated soil and removing the remaining non-volatile oil from the soil. A method for treating oil-contaminated soil, characterized by peeling and separating from the soil.   Add and mix quick lime or an additive based on quick lime into the soil contaminated with oil, and heat using the heat generated by the hydration reaction between the moisture in the oil-contaminated soil and the additive. The volatile component of the oil contained in the soil is volatilized and evaporated, and then the treated contaminated soil is washed to remove and separate and remove the remaining non-volatile oil from the soil. How to treat contaminated soil.   By adding and mixing quick lime or additives based on quick lime to the soil contaminated with oil, by the hydration reaction that occurs between the water in the oil-contaminated soil and additives based on quick lime or quick lime Slaked lime with increased surface area generated by reacting with the additive and moisture in the soil while removing the volatile components by volatilizing and evaporating them from the oil contained in the soil by heating using the generated heat In addition, after the non-volatile oil remaining in the soil is transferred, the treated contaminated soil is washed, and the non-volatile oil remaining in the soil is separated and removed from the soil. Method.   By adding and mixing quick lime or additives based on quick lime to the soil contaminated with oil, by the hydration reaction that occurs between the water in the oil-contaminated soil and additives based on quick lime or quick lime Slaked lime with increased surface area generated by reacting with the additive and moisture in the soil while removing the volatile components by volatilizing and evaporating from the oil contained in the soil by heating using the generated heat In addition, after transferring the non-volatile oil remaining in the soil, the treated contaminated soil is washed, the slaked lime adsorbing the non-volatile oil in the soil is dissolved in the washing liquid, and recovered, A method for treating oil-contaminated soil, characterized in that residual non-volatile oil is separated from the soil and separated and removed.   6. The method for treating oil-contaminated soil according to any one of claims 1 to 5, wherein the temperature of the washing liquid is increased by receiving heated soil to improve the washing treatment efficiency of the contaminated soil. .   By introducing slaked lime generated by the reaction with moisture in the soil into the cleaning process, the slaked lime was dissolved in the cleaning liquid to increase the pH of the cleaning liquid and improve the cleaning efficiency of contaminated soil The method for treating oil-contaminated soil according to any one of claims 1 to 5.   Addition and mixing of quicklime or quicklime-based additive to the soil contaminated with oil, hydration occurs between the quicklime or quicklime-based additive and moisture in the soil. A first treatment machine that uses heat generated by the reaction to heat and volatilizes and removes volatile components from the oil contained in the soil, and oil-contaminated soil treated by the first treatment machine. And a second processing machine that cleans the treated contaminated soil and separates / separates and removes the remaining non-volatile oil from the soil.   The first treatment machine for adding and mixing quick lime or an additive mainly composed of quick lime to the soil contaminated with oil, and the oil-contaminated soil mixed with the first treatment machine are received, and the quick lime or the quick lime is received. The heat generated by the hydration reaction that occurs between the additive containing the main component and the moisture in the soil is heated to remove the volatile components from the oil contained in the soil by volatilizing and transpiration. The third processing for accepting the oil-contaminated soil treated by the second processing device and the second processing device, washing the treated-contaminated soil, and separating / separating and removing the remaining non-volatile oil from the soil An oil-contaminated soil treatment system characterized by comprising a machine.

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